海底管道挖沟的数值模拟

海底管道在挖沟过程中可能受到较大的弯曲应力而出现屈服甚至断裂现象,因此,有必要确定管道在挖沟过程中的应力和变形分布。考虑管道自重和浮力的影响,采用有限元软件建立了海底管道挖沟时的力学模型,通过静力分析得到不同条件下的最大弯曲应力和变形,并将其拟合成公式。最后,通过实例计算,验证了拟合公式的准确性。结果表明：充水状态比空管状态所受弯曲应力大;管道埋设深度越深,所受弯曲应力越大;当要求的挖沟深度较大时,一次挖沟成型可能导致管道弯曲应力超出许用应力。

Numerical Simulation of Submarine Pipeline Trenching

Submarine pipeline may suffer from large bending stress in the process of trenching, resuhing in yielding even fracture. So it is necessary to ensure the stress and deformation distribution of trenching. This paper established the mechanics model of submarine pipeline trenching by using finite element software only considering the effective of gravity and buoyancy. Then it obtained maximum stress and deformation by static analysis under different conditions, and the results were fitted to formulas. Finally, this paper has verified the accuracy of the formulas by an example calculation. The results show that the water filling state is bigger than blank by bending stress, and the deeper the buried depth is, the larger bending stress is. Besides, when the specified depth is finished at a time, the bending stress may be beyond allowable stress.